I say just make vegetables with really delicious sauces (a heated mix of equal parts butter, brewers yeast and lemon juice is super delicious and I loved it as a kid) and don't let them get away with not trying at least one bite of everything you make. Mild curry and spaghetti sauce with green olives (separate from the noodles) were also some of my favorites as a child. And cucumber salad. and squash with a little maple syrup.
But I always had at least one vegetable that I loved at any point and my parents made a point of making sure to stock up on the things my brother and I liked at the time as well and introducing new things that we might like.